$ { {-1} \times \left[\begin{array}{rrr}{-2} & {4} & {-1} \\ {4} & {3} & {1}\end{array}\right] = {?} } $
Solution: To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rrr}{-1}\times{-2} & {-1}\times{4} & {-1}\times{-1} \\ {-1}\times{4} & {-1}\times{3} & {-1}\times{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{2} & {-4} & {1} \\ {-4} & {-3} & {-1}\end{array}\right]}$